Thiocyanate quaternary compounds and method of preparing the same



Patented June 18, 1946 THIOCYANATE QUATERNARY CO AND' METHOD OFPREPARING OUNDS SAME JosefPikl, Pitman, N. assign or'to E. I. du Pont deNemours & Company, Wilmington, DeL, a corporation of Delaware I NoDrawing." Application April 4, 1941,

'- Serial No.-386,845 K 1o Claims. (Cl. 260295).

This application is a continuation-in-part of my copending applicationSerial No. 363,524, filed October 30, 1940 (Patent No. 2,331,276, issuedOctober 5, 1943). This invention deals with novel organic compoundswhich may be characterized as being quaternary ammonium thiocyanatescontaining an acylamido-methylene radical as one substituent of thequaternary N -atom.-

It is an object of this invention to provide novel organic compoundswhich may be useful in the art of treating textile fabric to. endow thesame with water-repellency characteristics. It is a further object ofthis invention to provide a process for converting into water-solublecompounds, at least part of the reaction products described and claimedin my parent application above referred to. Other and further importantobjects of this invention will appear as the description proceeds. The.novel compounds of my present invention are characterized by the generalformula RYl7ICH:N(tert)-SCN wherein R is an aliphatic or alicyclicradicalcontalning at least 7 carbon atoms and being free fromwater-solubilizing groups; Y is a carbonyl link selected from the groupconsisting of CO, O-GO, NH-CO, CO.NH-CO and O-CO-NHCO; R stands forhydrogen, a lower alkyl group, or a lower alkylene group whose secondvalency is attached to the nitrogen atom of another radical of the formn-v-r z-cnr-Nmm-son as above defined; and finally, N(tert) stands forthe molecule of, an aliphatic or heterocycll tertiary base, for instancepyridine and its homologs, quinoline, trimethylamine, triethylamine,tetramethyl-methylene-diamlne, etc.

The novel compounds of this invention are interest in many fields, andhave for instance potential utility as insecticides. Their principalvalue however is in the field of water-proofingtextile fiber, inasmuchas I have found these compounds to posses excellent water-repellencyunsaturated, straight chain or branched chain, a

but having at least one straight chain of at least .9 carbon atoms.

The novel compounds are soluble both in organic solvents, for instancebenzene or carbontetrachloride, and in water. They are therefore adaptedfor application to the fiber from either type of bath. As alreadymentioned, an important quality of the novel compounds when used aswater-repellency agents is the absence of tendering of the fiber in theprocess of baking. Presumably, the thiocyanic acid liberated in thedryheating step is polymerized into harmless byproducts which do notattack the 'fiber as does for instance HCl in certain related agents incommon use nowadays. The novel agents may therefore be applied withoutany bufierlng or acid absorbing agents which are required in the relatedcompounds,

The quaternary ammonium thiocyanates of this invention may be preparedby reacting an amide methylol compound, for instance,stearamido-methylol, in a basic liquid medium, for instance pyridine,with the thiocyanic acid salt of the chosen tertiary base, for instancepyridine. The reaction then proceeds along lines indicate by the typicalequation below:

- soN GliHw-C oNH-crnoH U and the details of procedure may follow ingeneral the procedure laid out for analogous salts in U. 8; Patent No.2,146,392 of Baldwin et al.

A special process, however, according to this invention is to reactthe'preferred tertiary base, for'instance pyridine, upon the freshreaction products obtained in my parent application above referred to.

' These reaction products are themselves prepared, according to my saidparent application Serial No. 363,524, by reacting an acylamldomethylenehalide with a metal thiocyanate. A typical equation for this reactionis:

wherein R and B. have the same significance as above, while thepotassium salt of thiocyanic acid may be replaced by the correspondingsodium,

calcium or lead salt, or any other conveniently available form ofthiocyanlc acid.

of formula R CO'N -CHI-sCN when fresh. But upon standing it undergoesgradual rearrangement into the isomeric form therefore, the exactcomposition of this reaction product is probably a mixture of the two,in aproportion which depends on the age of the reaction product. I

The isothiocyanate form does not apparently react with tertiary bases togive quaternary ammonium salts; it is therefore better for the purposeOf this invention to react with the selected base upon the freshreaction product. Alternatively, one may apply this process to areaction product of any age under the penalty that only part of the samewill give the desired quaternary ammonium compound, which however can beseparated, if desired, from the unreacted isothiocyanate by making useof their different solubilities in water.

The preferred procedure according to this invention is to mix thereaction product of said parent application with the chosen tertiarybase and to let the mixture stand at room temperature for several hoursor days. The mixing may be done while the reaction product is insolution in an organic solvent, or after it has been recovered from thesolvent. If the chosen tertiary amine is a gas, such as in the case oftrimethylamine, the latter may be bubbled into the solution of thethiocyanomethylene reaction compound until 1 mol has been absorbed.

The reaction takes place at room temperature, usually in a few hours,but may be speeded up by warming to 50 to 80 C. for a short time.

The quaternary compounds formed from the thiocyanomethylene reactionproduct of my said parent application are generally quite soluble inorganic solvents like benzene and carbon tetrachloride, and highlyconcentrated solutions may' be prepared in these solvents, containing50% and more of the quaternary ammonium product. Upon evaporation of thesolvent, and occasionally on prolonged standing of the solution, thecrystalline quaternary ammonium thiocyanate can be obtained, whichdissolves in warm water giving very viscous foaming solutions. 4

The following examples in which parts by weight are given will serve toillustrate the preferred embodiments of this invention, without howeverany intent to limit this invention.

Example 1 220 parts 'of methylene distearamide were converted into thecorresponding di-chloromethyl compound by suspending the amide in 800parts of benzene and then adding in the course of 1 /2 hours 36 parts ofparaformaldehyde while pass-,

with charcoal and filtered from the inorganic salts and charcoal. Thesolution thus obtained was still slightly acid to Congo Red paper andwas neutralized by agitating the solution with some powdered potassiumcarbonate, calcium oxide or any other basic compound capable ofneutralizing the solution. This solution was mixed with 56 parts ofpyridine and allowed to stand at room temperature over night. Theoriginally rather thin solution had changed to a viscous oil. Uponevaporation of the solvent the residue was soluble in water giving aviscous slightly opalescent solution.

The said residue presumably was N,N- methylene -bis(stearamido methylenepyridini urn-thiocyanate, of the formula Two solutions of the same wereprepared: a 1% solution in water and a 0.5% solution in carbontetrachloride. Two pieces of cotton were impregnated respectively withthe two solutions. Both were air dried, and then heated for five minutesto 150 C. The two pieces were treated for a few minutes in hot water, towash out the last traces of pyridine and then ironed. Both samples werestrongly water-repellent and showed no noticeable tendering of thefiber. Upon washing the two samples with soap and hot water only a veryslight decrease in the repellency was observed.

Example 2 (containing 95% of the stearic acid radical) were dissolved in1000' parts of benzene, and then gradually 52 parts of paraformaldehydewere added, while passing in a slow stream of hydrogen chloride gas at60 C. After a few hours a clear solution results. The water was drawnoff and the benzene evaporated in vacuo.

110 parts of this low melting reaction product were dissolved in 100parts of dry benzene and then 72 parts of lead thiocyanate were added inthe course of ten minutes at 70 to C. After all of the lead compound wasadded the reaction mass was heated for twenty more minutes to to 88 C.Five parts of charcoal were added and the solution was filtered whiletill warm. The filtrate presumably contained in solution a mixture ofthiocyanomethylenecompounds of the formulas 11 uCONHCHr-SCNomroo-N-oHr'scN ems-co-m-cm-sou parts of potassium carbonate, filteredagain, and. then mixed with parts of pyridine.

3% aqueou solution were prepared from the above product and thefollowing fabrics were 5 impregnated therewith, then dried, baked, andfurther treated as in Example 1: r

Spun rayon Rayon crep Acetate taiieta Pure silk Wool trlcotine In allcases an excellent water repellency was little of their repellency.

Example 3 252 parts of octadecyl carbamate were dissolved in. 1600 partsof benzene heated to 60 C. and a stream of hydrogen chloride passed in.To this solution there were added in the course of 1 /2 hours, 72gramsof paraformaldehyde. When all the formaldehyde had been added thereaction was continued for one hour longer then the aqueous layerdrawnoff and the benzene solution evaporated in vacuo on the steam bath. The

residue, which amounted to 300 parts, contained 11.6% 01. It wasdissolved in 100 parts of benzene and added to 160 parts of dry leadthiocyanate suspended in 300 parts of hot benzene. The reaction mass wakept vigorously boiling for twenty minutes, then filtered while stillwarm and the filtrate allowed to cool to room temperature and treatedwith 50 parts of potassium carbamate f! 16 hours. Finally the solutionwas treated with 50 grams of calcium chloride for 5 hours and thenfiltered from the organic salts. The orange colored residue contained8.96% sulfur.

A 30% solution of this product in benzene was mixed with half its volumeof pyridine and then allowed to stand at room temperature for threedays. By this time aconsiderabie amount of a crystalline productseparated from the solution.

-*It was filtered off and gave in warm water a very viscous clearsolution. This product is the quaternary pyridinium thiocyanate. Thebenzene solution obtained fromthe above filtration was evaporated invacuo, and the residue obtained dissolved in water to a clear solution.When. cotton cloth wasimpregnated with a 1% aqueous solution of thispyridine compound and heated for a few minutes to 120 to; 150 C. astrongly water-repellent material was obtained which was not noticeablyimpaired by a washing process.

When in the above reaction pyridine was rep c d y t ylamine, a similarreaction occurred. The resulting product had similar propertie to thepyridinium compound. It gave clear,

viscous solutions in Water which decomposed with alkalies and renderedfibrous, material water-repellent.

Example 4 280 parts of a commercial mixture of stearic and palmiticacids (approximately 50:50l'were converted into the corresponding acidchlorides with thionylchloride. The crude reaction product, which wasfreed from excess acids by placing' the material under vacuum andwarming the charge, was dissolved in benzene and then, over a. period ofone hour, 43 parts oi hexamethylene tetramlne .were added while thecharge wa heated to 80 C. To the almost clear solution which resultedthere were added 228 parts of lead thiccyanate and then again heated tothe boil for twenty minutes and then the inorganic salts fil- 1 teredout. The resulting slightly yellowish solu- I tion was neutralized with30 parts of potassium carbonate and again filtered. Upon evaporation, alow melting hard solid remained which contained essentially one sulfurand two nitrogen atoms per long fatty chain.

v The benzenesolution obtained above was mixed with parts of pyridineand'allowed to stand at roomtemperature for 24 hours. The viscoussolution could be diluted with carbon tetra-chloride Example 5 282 partsof commercial stearic acid (containing stearic acid) were reacted with102 arts of phosphorous trichloride and the resulting acid chlorideheated for 3 hours on the steam bath while passing-under vacuum a slowstream of dry carbon dioxide through the liquid, until all the volatilematter was driven out. The pale yellow oil was diluted with 800 parts ofdry benzene, cooled to 0 C. and 44 grams of hexamethylene tetramineadded. After stirring for about 1 hour at 0 to 4 C. a clear solutionresulted. The reaction product'was now heated for 16 hours to 80 C. Thenthere were added 1'70 parts of lead thiocyanate and the charge was againheated to the boil for half an hour while distilling out 450 parts ofthe benzene. The reactionmas was cooled to room temperature and the leadchloride filtered out. To the pale yellow filtrate there were added 70parts of pyridine and the mixture was allowed to stand at roomtemperature for two days. The viscous clear solution could be diluted asdesired with benzene, carbon tetrachloride, trichloroethylene and otherfat solvents. For producing a satisfactory permanent waterproofing andsoftening efiect impregnation of the material with a .5% solution or a.25% solution in carbon tetrachloride was found suflicient.

One may also prepare an aqueous treating bath Example 6 parts of thethiocyanomethylene compound prepared according to Example 2 weredissolved in 100 parts of benzene and then reacted with 80 parts oftriethylamine. After 24 hours the solvent was evaporated. The residuewas soluble in water giving foaming viscous solutions.

When applied to cotton in the same way as the corresponding pyridiniumcompound it gives strongly water-repellent fibers.

In place of .triethylamine in the above experiment an equivalent, amountof trimethylamine, tetramethyl. methylene diamine or tetramethylethylene diamine may be used with the same results.

Example 7 parts of stearic acid chloride were dissolved in 750 parts ofcarbon tetrachloride and at-0 C., 22 parts of hexamethylene tetramineadded. After agitating for about one hour at 0 to 10 C. the almost clearsolution was heated to 80 C. for

' at a, concentration of 1% 16 hours and then 105 parts of leadthiocyanate added. The reaction mass was agitated vigorousof pyridinewhereupon a very viscous clear solution was obtained.

Instead of pyridine in the above experiment 25 parts oftetramethylmethylene diamine may be used as a tertiary base. Whenapplied to cellulosic or animal fibers in the same way as outlined inExample 1 good water-repellency is obtained. Instead of stearic acidchloride one may employ in the above example the halides of other acidssuch as lauric acid, myristic acid, palmitic acid, eicosanoic acid, oracids derived from fish oil having 20 and 22 carbon atoms as well asacids derived from the oxidation of parafiin, hydrogenated rosin acids,or the acids of montan wax. Y

Example 8 60 parts of methylol stearamide were suspended in 500 parts ofpyridine; 55 parts of pyridine thiocyanate wereadded and the mixture wasthen heated to 60 C. for hours. On cooling, the clear solution separateda copious amount of a colorless crystalline material, which was filteredoff and recrystallized from a mixture of methyl alcohol and ethylacetate. The crystals which were believed to be the stearamidomethylpyridinium thiocyanate had a melting point of 76 C. and were soluble inwarm water giving very viscous solutions, which could be thinned down bythe addition of some alcohol. They were also soluble in organic solventslike benzene or carbon tetrachloride.

When cotton cloth was impregnated with a 0.5% solution of this productin carbon tetrachloride and then air dried and heated for 5 minutes to150 C., it acquired a high degree of water-repellency. Furthermore, thecloth was not tendered to any detectable extent.

Example 9.

165 parts of octadecyl chlorocarbonate (C18H3'1O COC1 prepared fromoctadecyl alcohol and phosgene) were diluted with 750 parts of carbontetrachloride, then cooled to 0 C., and 22 parts of hexamethylenetetramine were added. After agitating for 1 hour at a temperature of 0to 10 C., the reaction mixture was heated for 10 hours to 80 C., andthen 105' parts of lead thiocyanate were added, while agitatingvigorously and distilling off part of the carbon tetrachloride.

The solution the inorganic salts filtered out.

To the resulting pale yellow solution 40 parts of pyridine were added.After several hours standing at room temperature, the solution becomesmuch more viscous and gives with water a foaming milky solution. Whenapplied to cotton and then subjected to a heating treatment the materialbecomes strongly water repellent.

In a similar manner, quaternary ammonium compounds may be prepared fromany of the thiocyanate reaction products mentioned in my parentapplication above referred to. For instance one may employ themethylene-thiocyais cooled to room temperature and I nates, preparedaccording to my said parent application, from the following amides:Stearamide: C11H3e-CONH: Octadecyl-carbamate: C1aHaa-O-CONH2Octadecyl-urea: C1aH31NH-CONH2 Stearyl-urea: CnHas-(JONH-CONH:Octadecyl-allo-phanate:

C1sH31-O-CONHCONH2 Methyl-stearamide: C1'1H35CONH--CH3Distearamido-methane:

C Has-C QNH Eicosanoic acid amide: C19H39CONH2 Montanic acid amide:C21H55-CONH2 z-hexadecyl-eicosanoic acid amide;

CIBHSPCHC oNH,

li 'Iridecamethylene-diamide:

0 ONE:

CONH:

Sebacic acid diamide:

0 ONE:

(0 HI) I 0 ONE:

In the case of methyl stearamide, when subjected for instance to theprocess of Example 2 above, the resulting quaternary compound will havethe probable formula When applied as water-repellents for textile ifiber, the novel compounds may be applied by themselves or Jointly withother textile finishing agents, for instance, waxes, rubber, syntheticresins, or polymerizable compounds which are soluble in the solvent usedfor the treatment, and which are generally employed for the purpose ofendowing the fabric with resistance to creasing. As such products may bementioned mono-molecular or polyvinyl acetate, methacrylic esters andethers of methylol urea. If the product is applied from aqueoussolution, it may be applied together with emulsions of waxes,polymerized methacrylic esters polyvinyl acetate, or in the presence ofpolyvinyl alcohol and partially saponified polyvinyl acetate.Furthermore, it may be applied in the presence of an excess offormaldehyde, under a pl-I-value suificiently acid to causepolymerization of the formaldehyde,

yielding a crush-resistant pile fabric. (See for instance, Heckert, U.S. P. 2,080,043.)

The said water-repellency treatment of textile stance British PatentNos. 466,817, 477,991, 493,- 920; U. S. Patent No. 2,160,176 andcopending wool, silk, nylon; and also to non-textile fibers,

for instance leather, paper or transparent cellulosic film.

The novel reagents of this invention may be applied tothe fabric fromeither aqueous or organic. solution, and have the advantage overquaternary ammonium compounds heretofore employed-.for this-purpose inthat they give a high degree of water-repellency without tender.-

ing the fiber. 'Ifheweakening of the fiber by the acid liberated in the'baking step (heating the impregnated fiber in the absence of moisture)constituted a source of annoyance to thetrade heretofore. Attempts havebeen made to solve the problem by adding buffers to theimpregnationbaths or by replacing the anion in such com-.

pounds as stearamido-methyl pyridinium chloride by anions of weak acidssuch as acetic, lactic, salicylic, glycollic or phthalic (U. S. PatentNos. 2,160,176 and 2,210,442). It seems, however, that the quaternarysalts of these weaker acids did not give such good water-'r'epellency asthe quaternary ammonium chlorides.

The reagents of the present invention combine high water-repellency withsafety to fiber and thus solve the above noxious problem of tenderingwithout recourse to buffers. Nevertheless bufiers maybe employed with mynovel agents if desired.

It will be understood that my invention is sus ceptible of widevariation in the details thereof without departing from the spirit ofthis invention, as defined by the subjoined claims:

Iclaim:

1. Quaternary ammonium compounds of the general formula wherein R is amember of the group consisting of aliphatic and alicyclic radicalscontaining at least 7 carbon atoms and being free from watersolubilizinggroups; Y is a carbonyl link selected from the group consisting of CO,OCO,

as above defined; and N(tert) stands for the molecule of a tertiary baseselected from the group consisting of aliphatic and heterocyclic Vtertiary nitrogenous bases.

2. A compound of the general formula A1kCON-CHrN(tert)-SCN wherein All:is an aliphatic hydrocarbon radical having at least 9 carbon-atoms; Rstands for a member of the group consisting of hydrogen, a

valency is attached to the nitrogen atom of a similar radical of theform I Alk-QO-N-CHi-Ndertl-SCN asherein defined; while N(tert) standsfor the molecule of a. tertiary base selected from the 'loweralkyl and alower alkylene whose other 10 group consisting of aliphatic andheterocyclic tertiary nitrogenous bases.

3. A compound of the general formula Aikcoivn-wnz-Ndem-scii wherein Alkstands for an aliphatic hydrocarbon radical having at least 9 carbonatoms while N (tert) stands for the molecule of a tertiary base selectedfrom the group consisting of aliphatic and heterocyclic tertiarynitrogenous bases.

4. A compound of the general formula wherein. Alk stands for analiphatic hydrocarbon radical having at least 9 carbon atoms whileN(tert) stands for the molecule of a tertiary base selected from thegroup consisting of aliphatic and heterocyclic tertiary nitrogenousbases.

5. stearamido-methyl-pyridinium thiocyanate, being the compound ,of theformula cnHar-C ONE-CH: N-SCN 6,N,N'-methylene-bis(stearamido-methyl-pyridinium thiocyanate), being thecompound represented by the formula CHEW-C 0NCH N-SCN 7.N,N'-methylene-bis(octadecoxy-carbamido methylene-pyridiniumthiocyanate), being the compound represented by the formula 8. Theprocess of preparing novel water-soluble organic compounds useful in thefield of waterproofing textile fiber, which comprises reacting with atertiary base upon the reaction product of a metal thiocyanate with amethylene halide compound of the general formula R-Y-N-CHa-X wherein Alkis an aliphatic hydrocarbon radical having at least 9 carbon atoms.

10. The process of preparing novel water-solu- 1o ble organic compoundsuseful in the field of waterproofing textile fiber, which comprisesreacting with a tertiary base upon a methylene thiocyanate compound 0!the formula wherein Alk is an aliphatic hydrocarbon radical having atleast; 9 carbon atoms.

J OSEF PIKL.

